1. Field of the Invention
The present invention relates to a networking apparatus and a telephony system.
2. Description of Related Art
As disclosed in JP-A-2006-229820 (Patent Document 1), there are known devices called VoIP gateways which permit PBXs (Private Branch Exchanges) and telephones to be connected to a VoIP (Voice over Internet Protocol) network to enable them to receive IP telephony services.
On the other hand, as disclosed in JP-A-2006-222666 (Patent Document 2), it is known that VoIP telephony is designed to offer functions similar to those offered by analog telephony and is in addition capable of being implemented with, by use of SIP (Session Initiation Protocol) functions, various value-added functions that are unfeasible in a system using analog telephones.
Inconveniently, however, according to Patent Documents 1 and 2 mentioned above, a system employing a VoIP gateway employs IP telephones only, and does not employ traditional analogue telephones. That is, analogue telephones are not furnished with VoIP functions, and accordingly VoIP gateways are not provided with ports for connection with analog telephones. Thus, disadvantageously, VoIP gateways do not allow use of analog telephones.
Nor are analog telephones furnished with SIP functions, and accordingly, disadvantageously, they cannot utilize the caller number display service which is relayed via a VoIP gateway.